From: hackbard Date: Thu, 10 Jan 2008 16:31:56 +0000 (+0100) Subject: small mods X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c4e0f74452033badf606ba05abc9c77b2331566;p=lectures%2Flatex.git small mods --- diff --git a/solid_state_physics/tutorial/1_06s.tex b/solid_state_physics/tutorial/1_06s.tex index f3d6992..4e965e3 100644 --- a/solid_state_physics/tutorial/1_06s.tex +++ b/solid_state_physics/tutorial/1_06s.tex @@ -51,11 +51,19 @@ =\ldots=5.97 \cdot 10^{-28} \, kg\frac{m}{s}$ \end{itemize} \item Phonon momentum necessary for transition:\\ - $p=\hbar \cdot \Delta k=\hbar \cdot 0.85 \, \frac{2\pi}{a} + $\Delta p=\hbar \cdot \Delta k=\hbar \cdot 0.85 \, \frac{2\pi}{a} =\frac{0.85 \, h}{a}=\ldots=1.04 \cdot 10^{-24} \, kg\frac{m}{s}$\\ $\rightarrow$ Phonon momentum 3 orders of magnitude below the momentum necessary for transition! - \item + \item \begin{itemize} + \item Photon momentum insufficient. + Momentum contribution of phonon (lattice vibration) required.\\ + $\Rightarrow$ Probability of transition very small. + \item Recombination energy of electron-hole pairs most probably + released as vibrational energy of the lattice.\\ + $\Rightarrow$ Only direct band gap semiconductors suitable for + effective photon generation. + \end{itemize} \end{enumerate} \section{\ldots}